Move dict repacking function to salt.utils

This allows the same repacking that is used in package management to be
used for lists of key/value pairs passed to ports.installed states.
Enhancements to freebsdports execution module

This adds a flag to showconfig that allows you to see the default
build options for a given port, as well as adds two new functions,
"list_all" and "search".
Add new ports state
Add new ports state to docs
Fix sphinx build warning
Merge pull request #7901 from terminalmage/freebsdports

More FreeBSD Ports goodness